Try swapping solenoids with the convertible.  Oil, low current, etc. can effect operation of the sometimes finicky devices.  If the police car issue continues, you can at least rule that out.
‘BTW: If the seal leaks at all, installing solenoid upside-down can inhibit draining.

6 VOLTS/POS. GRD. NW INDIANA

Alan, I’m glad to hear you have been able to get overdrive! Questions: how high is your idle speed set? Does your throttle linkage readily snap back to idle setting every time? And, when you engage your kickdown switch, does it interrupt the ignition briefly like it’s supposed to?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Peeeot....I don't have a tachometer but I would estimate the idle speed at maybe 500-600 RPM.  I was having trouble with the accelerator linkage sticking and not quickly returning to slow idle.  I solved that problem last week when I fabricated a new longer adjustable rod which attaches to the carb.  The rod that was on the car was a little too short so the linkage would hang up without returning to slow idle.  Yes, when I engage the kickdown switch the engine momentarily cuts out. 

Alan, I asked about the idle speed because for a while my car was hanging up slightly when I would back off the gas due to a minor linkage issue. When it did this, the engine would only slow to something like 800-1000 rpm, and I would not get an overdrive shift until I hooked my toe under the pedal and pulled it back to drop the rpms down to 650 or less. There has to be a certain amount of “drag” from the engine on the input side of the overdrive to get the blocker ring to move out of the pawl’s way. In your case, if the shift only happens when you mash the kickdown switch followed by pedal release, perhaps the momentary loss of ignition paired with throttle release is causing the engine to drop rpms very quickly and thus generate the needed “drag” to shift the blocker ring.

I need to look at the manual again but I think there was a comment about the amount of friction between the blocker ring and the sun gear plate.

What are you using for gearbox oil?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

I am using STP 80-90 weight gear oil.

Hmmm, probably the wrong stuff. STP says it's for axles and non-synchro transmissions. It likely contains hypoid additives for axles. Hypoid additives aren't good for our transmissions because they attack the brass synchronizers. These transmissions want a straight mineral oil without hypoid additives. Tractor Supply has it under the brand name Traveller Ford Tractor Transmission Oil. NAPA  Auto Parts also has it but may need to order it from their warehouse.

I agree with Dobie, GL-5 hypoid gear oil is not recommended for the trans or overdrive. I use Redline MT-85 which is a GL-4 intended for manual transmissions with brass synchros. Viscosity is comparable to the factory recommendation as well.

I can’t say whether the use of hypoid gear oil could be affecting overdrive engagement.



1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Sometime in the past I read not to use synthetic oils, which GL5 are in OD trans. It was said they are too sticky and can effect the pawl engagement some how?. I've always used GL4 in my two OD trans.

Gl-5 does not indicate synthetic and most modern GL-5 is safe with yellow metals.  If in doubt, refer to the manufacturer of the particular oil you want to use.


Lawrenceville, GA

Dobie.....I checked the Tractor Supply Website but I don't see any transmission oil, only motor and hydraulic oil????